Not tried a 5.5 but just swapped from an Orange 5 to a Tracer. The difference between the 2 is phenomenal. Tracer is streets ahead of the Orange and I find it a much more stable pedalling platform, the rear wheel is almost glued to the ground whereas the Orange bounced around everywhere.
I have Lyriks on my Tracer and it works really well. Turns the bike into a real battle bus that will deal with anything you throw at it. 160mm travel takes the head angle to around 67.5 degrees i think, but the front does not feel wandery at all when climbing, and gets even better when you head downhill.
Whereabouts are you, I'm in Bristol if you want to have a go on mine.